Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C319/00—Preparation of thiols, sulfides, hydropolysulfides or polysulfides
  • C07C319/22—Preparation of thiols, sulfides, hydropolysulfides or polysulfides of hydropolysulfides or polysulfides
  • C07C319/24—Preparation of thiols, sulfides, hydropolysulfides or polysulfides of hydropolysulfides or polysulfides by reactions involving the formation of sulfur-to-sulfur bonds

Definitions

• the invention relates to the production of organic polysulphides of the type RS n R where the two symbols R, which may be identical or different, each represent a hydrocarbon radical and n is a number ranging from 3 to 8, in particular from 4 to 6.
• the subject of the present invention is, therefore, a process for the preparation of organic polysulphides by the action of sulphur on a mercaptan, characterized in that the reaction is carried out in the presence of a thioxanthate formed by combination of carbon disulphide with a mercaptide.
• the thioxanthate may be prepared separately by mixing approximately equimolar quantities of a mercaptan, a base and carbon disulphide in an inert organic solvent (for example methanol) and isolated by evaporation of the solvent.
• an inert organic solvent for example methanol
• the best means of carrying out the process according to the invention consists in forming the thioxanthate in situ by stirring a mixture of mercaptan, base and carbon disulphide for a few minutes before introducing the sulphur necessary for the formation of the desired polysulphide.
• the quantity of carbon disulphide to be used may vary within wide limits, provided that it is at least the molar equivalent of that of the base used. It is, however, advantageous to work with an excess of carbon disulphide with respect to the base, and, more particularly, using a volume of carbon disulphide which is between 0.5 and 1.5 times that of the mercaptan used.
• the hydrocarbon radical may be aliphatic, cycloaliphatic or aromatic.
• alkyl mercaptans containing 2 to 15 carbon atoms and, more particularly, those with a tertiary alkyl radical are preferred.
• the respective quantities of sulphur and mercaptan to be used depend on the polysulphide desired, that is to say on the mean number of sulphur atoms per molecule of polysulphide.
• the ratio: gram-atoms of sulphur/moles of mercaptan may vary from 0.5 to 5. It is preferably between 1.5 and 2.5 to obtain polysulphides whose mean number of sulphur atoms per molecule is from 4 to 5.
• the base used may be of an inorganic or organic nature.
• a metal hydroxide such as, for example, sodium or potassium hydroxide, or an amine, in particular a trialkylamine such as, for example, triethylamine, may be used.
• the base may be used in small quantities (for example from 0.01 to 2 mole per 100 moles of mercaptan), but also in large quantities (for example a molar equivalent with respect to the mercaptan).
• the reaction according to the invention does not necessitate heating and is, therefore, preferably carried out at ambient temperature (10°-20° C.).
• ambient temperature 10°-20° C.
• the different polysulphides obtained according to the invention have a characteristic distribution. In fact, monosulphide is not observed, neither is disulphide and generally little trisulphide; and major product is tetrasulphide accompanied by a small amount of heavier sulphides.
• the relatively low proportion of heavy sulphides (n>5), in spite of the fact that the number n is fairly high, allows the polysulphides obtained according to the invention to be stable, that is to say not to deposit sulphur on storage and to remain clear and yellow.
• the polysulphides obtained by other methods contain a large amount of heavy sulphides; they easily deposit sulphur and become turbid.
• Example 1-b is repeated, except that it is carried out in the absence of carbon disulphide and the mixture is stirred for 6 hours at ambient temperature.
• a polysulphide of mean formula (CH 3 ) 3 CS 4 .9 C(CH 3 )hd 3 is obtained in the form of a clear yellow liquid which does not blacken acetate paper.
• a mixture of 80 ml (0.861 mole) isopropyl mercaptan, 80 ml carbon disulphide and 0.6 ml (4.3 millimoles) triethylamine are stirred for 15 minutes at ambient temperature. 56.6 g (1.768 mole) of solid sulphur are then added and stirring is continued for one hour.
• the mean number of sulphur atoms per molecule is 4.9 and the yield is 96%.
• Example 5 If Example 5 is repeated, but with only 34.3 g (1.065 mole) sulphur, 76.5 g of a clear yellow polysulphide which does not blacken acetate paper and whose level of residual mercaptan is less than 5 ppm are obtained.
• Example 4 This is carried out in the same way as Example 4 with 80 ml (0.465 mole) tert-octyl mercaptan, 80 ml carbon disulphide, 0.4 ml triethylamine and 29.8 g (0.93 mole) sulphur.
• Example 4 This is carried out in the same way as Example 4 with 100 ml (0.425 mole) tert-dodecyl mercaptan, 100 ml carbon disulphide, 0.5 ml triethylamine and 27.2 g (0.85 mole) sulphur. Because the sulphur dissolves slowly, stirring is maintained for 4 hours before bubbling nitrogen through the mixture. The evaporation at 60° C. under 1600 Pa must be carried out for 5 hours so that the clear yellow liquid only blackens acetate paper slightly.
• the level of residual mercaptan is less than 5 ppm.
• Microanalysis indicates a sulphur content of 31.7%, corresponding to a mean number of 4.9 atoms of sulphur per molecule.
• the mean number of sulphur atoms is 4 in place of the 4.3 of example 6.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)

Applications Claiming Priority (2)

Publications (1)

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Cited By (7)

Citations (2)

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• 1988
  • 1988-08-23 FR FR8811131A patent/FR2635775B1/fr not_active Expired - Fee Related
• 1989
  • 1989-07-27 US US07/385,404 patent/US4933481A/en not_active Expired - Lifetime
  • 1989-08-01 CA CA000607170A patent/CA1308741C/fr not_active Expired - Lifetime
  • 1989-08-16 EP EP89402293A patent/EP0356318B1/de not_active Expired - Lifetime
  • 1989-08-16 ES ES198989402293T patent/ES2036047T3/es not_active Expired - Lifetime
  • 1989-08-16 DE DE8989402293T patent/DE68903313T2/de not_active Expired - Fee Related
  • 1989-08-16 AT AT89402293T patent/ATE81849T1/de not_active IP Right Cessation
  • 1989-08-18 JP JP1212861A patent/JPH02101058A/ja active Granted
  • 1989-08-21 AU AU40108/89A patent/AU615785B2/en not_active Ceased
• 1993
  • 1993-01-13 GR GR930400033T patent/GR3006772T3/el unknown

Patent Citations (2)

Non-Patent Citations (1)

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